Soluble estradiol capsule for vaginal insertion

ABSTRACT

According to various embodiments of this disclosure, pharmaceutical formulations comprising solubilized estradiol are provided. In various embodiments, such formulations are encapsulated in soft capsules which may be vaginally inserted for the treatment of vulvovaginal atrophy.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to the following U.S. patent applications: U.S. Provisional Application Ser. No. 61/661,302, entitled “ESTRADIOL FORMULATIONS,” which was filed on Jun. 18, 2012; U.S. Provisional Application Ser. No. 61/662,265, entitled “PROGESTERONE FORMULATIONS,” which was filed on Jun. 20, 2012; U.S. patent application Ser. No. 13/684,002, entitled “NATURAL COMBINATION HORMONE REPLACEMENT FORMULATIONS AND THERAPIES,” which was filed Nov. 21, 2012; U.S. Provisional Application Ser. No. 61/745,313, entitled “SOLUBLE ESTRADIOL CAPSULE FOR VAGINAL INSERTION,” which was filed on Dec. 21, 2012; U.S. Patent Application Serial No. PCT/US2013/023309, entitled “TRANSDERMAL HORMONE REPLACEMENT THERAPIES,” which was filed Jan. 25, 2013; and U.S. patent application Ser. No. 13/843,428, entitled “NATURAL COMBINATION HORMONE REPLACEMENT FORMULATIONS AND THERAPIES,” which was filed Mar. 15, 2013. All aforementioned applications are hereby incorporated by reference herein in their entirety.

BACKGROUND Field

Postmenopausal women frequently suffer from certain vaginally localized states including, for example, atrophic vaginitis or vulvar and vaginal atrophy (hereinafter “vulvovaginal atrophy” or “VVA”) with symptoms including, for example, dryness, itching, soreness, irritation, bleeding and dyspareunia; with urinary frequency, urgency, urinary discomfort and incontinence also occurring (singularly and collectively, “estrogen-deficient urinary state(s)”). For the sake of clarity, the terms “atrophic vaginitis” and vulvovaginal atrophy are used herein interchangeably. The molecular morphology of VVA is well known in the medical field.

Each of these VVA-related states, inter alia, are symptoms associated with decreased estrogenization of the vulvovaginal tissue, and can even occur in women treated with oral administration of an estrogen-based pharmaceutical drug product. Although VVA is most common with menopausal women, it can occur at any time in a woman's life cycle.

VVA-related states are generally treated with local administration of an estrogen-based natural or synthetic hormone in the form of a topically applied gel or cream, or through vaginal insertion of a compressed tablet. These forms of administration can provide low levels of circulating estrogen but are not intended to contribute to the treatment of other states related to estrogen deficiencies typically treated via administration of a systemically absorbed estrogen product. For example, such systemically absorbed products include orally administered formulations as well as creams, gels, sprays, and transdermally delivered products. However, vaginal gels and creams may rub, wear or wash off before the estrogen is fully absorbed into the local tissue. In addition, various commercially available estrogen-containing creams contain an alcohol such as benzyl alcohol and/or stearyl alcohol. The use of such products may result in itching or burning when applied. The above referenced vaginal creams and gels require insertion via a reusable vaginal applicator/plunger for which patients complain of difficulty to accurately dose, discomfort or pain upon insertion, and increased trauma to the genital mucosa all in relation to the vaginal applicator. Furthermore, the reusable applicator/plunger is also difficult to clean resulting in hygienic concerns as well as increased rates of infection all decreasing the ongoing compliance of the therapy.

Similarly, vaginal suppositories in the form of inserted tablets may not fully dissolve, reducing the effective dose of absorbed estrogen; may cause unwanted and unnecessary vaginal discharge; may cause an increase of vulvovaginal pruritus and/or back pain; and the insertion, itself, using the applicator provided with the reference-listed tableted drug, Vagifem® (Novo Nordisk; Princeton, N.J.), may cause a rupture of the vaginal fornix.

There has been at least one attempt at providing a soluble or suspended estrogen capsule for vaginal insertion as described in U.S. Pat. No. 6,060,077 (the '077 patent). The '077 patent provides for a non-systemic treatment for vaginal dryness in menopausal women using an immediate or slow-release formulation comprising a natural estrogen compound in solution or suspension in a lipophilic agent, a hydrophilic gel-forming bioadhesive agent, a gelling agent for the lipophilic agent, and a hydrodispersible agent in a hard or soft capsule. It is specifically stated that these formulations are designed to avoid systemic passage of estradiol following administration. Once in contact with vaginal secretions, these formulations require the presence of the hydrophilic gel-forming bioadhesive agent to react with the hydrodispersible agent to form an estrogen-containing emulsion to facilitate absorption. A practical issue arises when attempting to use this medicament when vaginal secretions are required to activate the formulation while the treatment is designed to treat vaginal dryness.

Accordingly, an estrogen-based vaginal suppository that provides an ease of administration/insertion, improved safety of insertion, lacking or minimizing vaginal discharge following administration, and that does not require vaginal secretions to activate the formulation could provide a more effective dosage form with improved efficacy, safety and patient compliance.

SUMMARY

According to various embodiments of this disclosure, encapsulated pharmaceutical formulations comprising solubilized estradiol are provided. Such formulations are encapsulated in soft capsules which are vaginally inserted for the treatment of vulvovaginal atrophy.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present invention is particularly pointed out and distinctly claimed below. A more complete understanding of the present invention, however, may best be obtained by referring to the detailed description and claims when considered in connection with the figures, wherein like numerals denote like elements and wherein:

FIG. 1 is a flow diagram illustrating a process in accordance with various embodiments of the invention; and

FIG. 2 illustrates a suppository in accordance with various embodiments of the invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Definitions

The term “active pharmaceutical ingredient” as used herein, means the active compound(s) used in formulating a drug product.

The term “AUC,” as used herein, refers to the area under the curve that represents changes in blood concentration of an active pharmaceutical ingredient (e.g., estradiol, which is also referred to in the literature as 17β-estradiol, oestradiol, or E2) over time.

The term “bioavailability”, as used herein means the concentration of an active ingredient (e.g., estradiol) in the blood (serum or plasma). The relative bioavailability may be measured as the concentration in the blood (serum or plasma) versus time. Pharmacokinetic (PK) indicators that may be used to measure and assess bioavailability are determined by suitable metrics including AUC, Cmax, and, optionally, Tmax.

The term “bioequivalent” means that a test drug product provides similar bioavailability compared to a reference drug product pursuant to the criteria set forth for bioequivalence by the United States Food and Drug Administration, as amended. In general, the bioavailability of an active pharmaceutical ingredient in a bioequivalent drug product is 80 to 125% of the bioavailability of the active pharmaceutical ingredient of the reference drug product concerning AUC and Cmax.

The term “bio-identical hormones”, as used herein, means those synthetically-derived compounds which are identical in chemical structure to the hormones naturally produced in vivo. These natural or bio-identical hormones are synthesized from various ingredients to match the chemical structure and effect of estradiol or estrone, or estriol (the 3 primary estrogens).

The term, “Cmax” as used herein, refers to the maximum value of blood concentration shown on the curve that represents changes in blood concentrations of an active pharmaceutical ingredient (e.g., estradiol) over time.

The term “co-administered” as used herein, means that two drug products are administered simultaneously or sequentially on the same or different days.

The term “drug product” as used herein means at least one active pharmaceutical ingredient in combination with at least one excipient and provided in unit dosage form.

The term “excipients,” as used herein, refer to non-active pharmaceutical ingredients such as carriers, solubilizing agents, oils, lubricants and others used in formulating pharmaceutical products. They are generally safe for administering to animals, including humans, according to established governmental standards, including those promulgated by the United States Food and Drug Administration.

The term “natural,” as used herein with reference to hormones discussed herein, means bio-identical hormones synthesized to match the chemical structure and effect of those that occur naturally in the human body (endogenous). An exemplary natural estrogen is estradiol (also described as 17β-estradiol and E2).

The term “medium chain,” as used herein means any medium chain carbon-containing substance, including C4-C18, and including C6-C12 substances, fatty acid esters of glycerol, fatty acids, and mono-, di-, and triglycerides of such substances. For further illustration, C6-C14, C6-C12 fatty acids, and C8-C10 fatty acids are all medium chain fatty acids and may be used in instances in which this specification calls for use of medium chain fatty acids, e.g., medium chain fatty acid esters of glycerol or other glycols.

The term “reference listed drug product” as used herein means Vagifem®.

The term “solubilizer,” as used herein, means any substance or mixture of substances that may be used to enhance the solubility of estradiol, including, for example and without limitation, appropriate pharmaceutically acceptable excipients, such as solvents, co-solvents, surfactants, emulsifiers, oils and carriers.

The term “treatment”, as used herein, or a derivative thereof, contemplates partial or complete inhibition of the stated disease state or condition when a formulation as described herein is administered prophylactically or following the onset of the disease state for which such formulation is administered. For the purposes of the present disclosure, “prophylaxis” refers to administration of the active ingredient(s) to an animal, typically a human, to protect the animal from any of the disorders set forth herein, as well as others.

The term, “Tmax” as used herein, refers to the time that it takes for an active pharmaceutical ingredient (e.g., estradiol) and/or estrone blood concentrations to reach the maximum value.

Description

Provided herein are pharmaceutical formulations comprising solubilized estradiol (in various embodiments, at least 90% in solution); providing said formulations do not embrace within the fill one or more of the following components: a hydrophilic gel-forming bioadhesive (e.g., mucoadhesive) agent; a lipophilic agent; a gelling agent for the lipophilic agent, and/or a hydrodispersible agent. The hydrophilic gel-forming bioadhesive agent may provide or exclude one or more of a: carboxyvinylic acid; hydroxypropylcellulose; carboxymethylcellulose; gelatin; xanthane gum; guar gum; aluminum silicate; or mixtures thereof. The lipophilic agent may provide or exclude one or more of a: liquid triglyceride; solid triglyceride (with a melting point of about 35° C.); carnauba wax; cocoa butter; or mixtures thereof. The gelling agent may provide or exclude one or more of a hydrophobic colloidal silica. The hydrodispersible agent may provide or exclude one or more of a: polyoxyethylene glycol; polyoxyethylene glycol 7-glyceryl-cocoate and mixtures thereof.

Generally, the pharmaceutical formulations described herein are prepared and administered as filled capsules, typically soft capsules of one or more materials well known in the art including, for example and without limitation, soft gelatin capsules. However, in various embodiments, pharmaceutical formulations described herein are prepared as a gel, cream, ointment, transdermal delivery system or like preparation.

Other aspects of the present disclosure include the use of formulations as described herein for the treatment of vulvovaginal atrophy including the treatment of at least one VVA symptom including, for example and without limitation, dryness, itching, soreness, irritation, bleeding and dyspareunia.

Another aspect of the present disclosure provides uses of the formulations described herein for the treatment of estrogen-deficient urinary states.

Another aspect of the present disclosure provides alcohol-free or substantially alcohol-free formulations, and uses thereof. Among others, the formulations offer improved comfort during use, thus tending to enhance patient compliance.

The methods of treatment described herein are generally administered to a human female.

A further aspect of the present invention provides formulations of the present invention wherein circulating blood level concentrations following administration of a formulation of the present invention are bioequivalent to circulating blood level concentrations following administration of the reference listed drug product, as determined through the completion of a bioequivalence clinical study.

The formulations of the present disclosure may also be vaginally administered with or without the co-administration of an orally administered estrogen-based (or progestin-based or progestin- and estrogen-based) pharmaceutical drug product, or patch, cream, gel, spray, transdermal delivery system or other parenterally-administered estrogen-based pharmaceutical drug product, each of which can include natural, bio-similar, or other synthetic or derived estrogens and/or an administered progestin. As used herein, the term “progestin” means any natural or man-made substance that has pharmacological properties similar to progesterone.

Modulation of circulating estrogen levels provided via the administration of a formulation of the present disclosure, if any, are not intended to be additive to any co-administered estrogen product and its associated circulating blood levels.

The timing of administration of a formulation of the present disclosure may be conducted by any safe means as prescribed by an attending physician. Typically, a patient will insert one capsule intra-vaginally each day for 14 days, then one capsule twice weekly for the remaining time prescribed by such physician. Intra-vaginal insertion may be via the use of an applicator or without an applicator via use of the patient's digits. Use of an applicator or otherwise requires due care as to not puncture or tear surrounding tissue.

Estradiol dosage strengths can vary. For formulations of the present disclosure, estradiol (or estradiol equivalent to the extent such estradiol is in a hydrated or other form requiring compensation therefore) dosage strength of is at least about 1 microgram (mcg), at least about 2.5 mcg; at least about 5 mcg; at least about 10 mcg, from about 1 mcg to about 10 mcg, from about 10 mcg to about 25 mcg, about 1 mcg, about 2.5 mcg, about 5 mcg, about 10 mcg and about 25 mcg. To protect against adverse effects of estradiol, the lowest possible dose should be used for treatment of VVA and other states set forth herein. In one embodiment, the dosage is about 10 mcg; in another the dosage is about 25 mcg.

Also provided are soft capsules designed for ease of insertion and to hold the capsule in place until the contents therein are completely released. In various embodiments, softgel capsules in accordance with various embodiments are sized to comfortably fit within a human vagina. Thus, the softgel capsules may comprise any dimension capable of fitting into a human vagina. With reference to FIG. 2, softgel capsule 200 is illustrated. Softgel capsule 200 comprises fill material 202 and gelatin 204. Gelatin 204 has a thickness represented by space 208. Space 208 comprises a distance of 0.108 inches. The distance from one end of softgel capsule 200 to another is represented by space 206. Space 206 comprises a distance of 0.690 inches. The size of softgel capsule 200 may also be described by the arc swept by a radius of a given length. For example, arc 210, which is defined by the exterior of gelatin 204, is an arc swept by a radius of 0.189 inches. Arc 212, which is defined by the interior of gelatin 204, is an arc swept by a radius of 0.0938 inches. Arc 214, which is defined by the exterior of gelatin 204 opposite arc 210, is an arc swept by a radius of 0.108 inches.

Estradiol can be formulated pursuant to the teachings below. These formulations can be prepared for vaginal insertion in a single unit dosage form or as otherwise specified herein.

In various embodiments, estradiol is solubilized at least once during manufacturing and, in various embodiments, estradiol is solubilized at one point following administration. Solubility may be expressed as a mass fraction (% w/w). As used herein, the term “soluble” or “solubilized” means that the estradiol is: at least about 85% soluble, at least 90% soluble, at least 95% soluble and, frequently, is 100% soluble. % Solubility is expressed herein as a mass fraction (% w/w, also referred to as wt %).

Upon release of the fill into the vaginal canal following insertion of a capsule of the present disclosure, estradiol may be locally absorbed into body tissues.

In various embodiments, the solubilizing agent is selected from at least one of a solvent or co-solvent. Suitable solvents and co-solvents include any mono-, di- or triglyceride and glycols, and combinations thereof.

Solubilized estradiol of the present disclosure is prepared via blending estradiol with a pharmaceutically acceptable solubilizing agent including for example and without limitation, at least one medium chain fatty acid such as medium chain fatty acids consisting of at least one mono-, di-, or triglyceride, or derivatives thereof, or combinations thereof (collectively, “glycerides”). In various embodiments, solubilized estradiol of the present disclosure may also comprise at least one glycol or derivatives thereof or combinations thereof (collectively, “glycols”) and/or combinations of such at least one glyceride and glycol. Glycols may be used as solubilizing agents and/or to adjust viscosity and, thus, may be considered thickening agents, as discussed further herein. Optionally added are other excipients including, for example and without limitation, anti-oxidants, lubricants and the like. Sufficient solubilizing agent(s) is/are used to solubilize estradiol.

Pharmaceutically acceptable solubilizing agents include, for example and without limitation, the use of at least one of a caproic fatty acid; a caprylic fatty acid; a capric fatty acid; a tauric acid; a myristic acid; a linoleic acid; a succinic acid; a glycerin; mono-, di-, or triglycerides and combinations and derivatives thereof; a polyethylene glycol; a polyethylene glycol glyceride (GELUCIRE (polyethylene glycol glyceride) GATTEFOSSE SAS, Saint-Priest, France); which can be used herein as a solubilizing agent or as an anionic surfactant); a propylene glycol; a caprylic/capric triglyceride (MIGLYOL (caprylic/capric triglyceride)); SASOL Germany GMBH, Hamburg); MIGLYOL includes MIGLYOL 810 (caprylic/capric triglyceride), MIGLYOL 812 (caprylic/capric triglyceride), MIGLYOL 816 (caprylic/capric triglyceride) and MIGLYOL 829 (caprylic/capric/succinic triglyceride)); a caproic/caprylic/capric/lauric triglyceride; a caprylic/capric/linoleic triglyceride; a caprylic/capric/succinic triglyceride; a propylene glycol monocaprylate; propylene glycol monocaprate; (CAPMUL PG-8 (propylene glycol monocaprylate) and CAPMUL PG-10 (propylene glycol monocaprate); the CAPMUL brands are owned by ABITEC, Columbus Ohio); a propylene glycol mono- and dicaprylate; a propylene glycol mono- and dicaprate; medium chain mono- and di-glycerides (CAPMUL MCM (medium chain mono- and diglycerides)); a diethylene glycol mono ester (including 2-(2-Ethoxyethoxy)ethanol: TRANSCUTOL (diethylene glycol monoethyl ether)); a diethylene glycol monoethyl ether; glyceryl mono- and di-caprylates; propylene glycol; 1,2,3-propanetriol (glycerol, glycerin, glycerine) esters of saturated coconut and palm kernel oil and derivatives thereof; triglycerides of fractionated vegetable fatty acids, and combinations and derivatives thereof. In various embodiments, propylene glycol is used in a cream or ointment.

These solubilizers, as defined herein, and combinations thereof, can be used to form solubilized estradiol formulations of the present disclosure.

At least one anionic and/or non-ionic surfactant can be used in additional embodiments of the presently disclosed formulations containing solubilized estradiol.

Exemplary non-ionic surfactants may include, for example and without limitation, one or more of oleic acid, linoleic acid, palmitic acid, and stearic acid. In further embodiments, the non-ionic surfactant may comprise polyethylene sorbitol esters, including polysorbate 80, which is commercially available under the trademark TWEEN 80 (polysorbate 80) (Sigma Aldrich, St. Louis, Mo.). Polysorbate 80 comprises approximately 60%-70% oleic acid with the remainder comprising primarily linoleic acids, palmitic acids, and stearic acids. Polysorbate 80 may be used in amounts ranging from about 5 to 50%, and in certain embodiments, about 30% of the formulation total mass. In various other embodiments, the non-ionic surfactant is selected from one or more of glycerol and polyethylene glycol esters of long chain fatty acids, for example, lauroyl macrogol-32 glycerides and/or lauroyl polyoxyl-32 glycerides, commercially available as GELUCIRE, including, for example, GELUCIRE 39/01 (glycerol esters of saturated C12-C18 fatty acids), GELUCIRE 43/01 (hard fat NF/JPE) and GELUCIRE 50/13 (stearoyl macrogol-32 glycerides EP, stearoyl polyoxyl-32 glycerides NF, stearoyl polyoxylglycerides (USA FDA IIG)). These surfactants may be used at concentrations greater than about 0.01%, and typically in various amounts of about 0.01%-10.0%, 10.1%-20%, and 20.1%-30%.

Ratios of solubilizing agent(s) to surfactant(s) can vary depending upon the respective solubilizing agent(s) and the respective surfactant(s) and the desired physical characteristics of the resultant formulation of solubilized estradiol. For example and without limitation, CAPMUL MCM and a non-ionic surfactant can be used at ratios including 65:35, 70:30, 75:25, 80:20, 85:15 and 90:10. Other non-limiting examples include: CAPMUL MCM and GELUCIRE 39/01 can be used in ratios including, for example and without limitation, 6:4, 7:3, and 8:2; CAPMUL MCM and GELUCIRE 43/01 can be used in ratios including, for example and without limitation, 7:3, and 8:2; CAPMUL MCM and GELUCIRE 50/13 can be used in ratios including, for example and without limitation, 7:3, and 8:2, and 9:1.

Another exemplary non-ionic surfactant includes PEG-6 palmitostearate and ethylene glycol palmitostearate, which is available commercially as TEFOSE 63 (“Tefose 63”; GATTEFOSSE SAS, Saint-Priest, France) which can be used with, for example, CAPMUL MCM having ratios of MCM to TEFOSE 63 of, for example, 8:2 and 9:1. Additional examples of solubilizing agents with non-ionic surfactants include, for example, MIGLYOL 812:GELUCIRE 50/13 and MIGLYOL 812:TEFOSE 63.

Anionic surfactants are well known and can include, for example and without limitation: ammonium lauryl sulfate, dioctyl sodium sulfosuccinate, perfluoro-octane sulfonic acid, potassium lauryl sulfate and sodium stearate.

Non-ionic and/or anionic surfactants can be used alone or with at least one solubilizing agent or can be used in combination with other surfactants. Accordingly, such surfactants, or any other excipient as set forth herein, should be used to provide solubilized estradiol, upon release from a vaginally-inserted capsule, with consistency of the solubilized estradiol that promotes absorption and minimizes vaginal discharge, particularly when compared to the vaginal discharge frequently occurring following use of a VAGIFEM tablet.

Moreover, the estradiol in the formulations disclosed herein need not be fully solubilized (e.g., at least 98% in solution) at the time of administration/insertion but, rather, needs to be substantially solubilized at the time of release from the vaginally-inserted capsule. As such, the solubilizing agents taught herein, with or without additional excipients other than the solubilizing agents, may be in the liquid or semi-solid form upon administration providing the estradiol containing solubilizing agents and other excipients permit flow to fill capsules. To the extent the estradiol is not fully solubilized at the time of administration/insertion, the estradiol should be substantially solubilized at a temperature of about 37° C. (e.g., body temperature) and, generally, at a pH of about 4.5. In another embodiment, at least one thickening agent may be added to formulations of the present disclosure. The viscosity of the solubilized estradiol may depend upon the solubilizing agent(s) used, the addition of other excipients to the formulation preparation and the desired or required final viscosity required to optimize absorption of the solubilized estradiol. In certain embodiments, the surfactant(s) referenced herein above may provide thickening of the solubilized estradiol such that, upon release, will aid the estradiol in being absorbed by the vaginal mucosa while minimizing vaginal discharge, particularly when compared to the vaginal discharge frequently occurring following use of a Vagifem tablet. Examples of other such thickening agents include, for example and without limitation, hard fats; propylene glycol; a mixture of hard fat EP/NF/JPE, glyceryl ricinoleate, ethoxylated fatty alcohols (ceteth-20, steareth-20) EP/NF (commercially available as OVUCIRE 3460 (mixture of hard fat EP/NF/JPE (and) glyceryl ricinoleate (and) ethoxylated fatty alcohols (ceteth-20, steareth-20) EP/NF) (Gattefosse, Saint-Priest France); a mixture of hard fat EP/NF/JPE, glycerol monooleate (type 40) EP/NF (commercially available as OVUCIRE WL 3264 (mixture of hard fat EP/NF/JPE (and) glycerol monooleate (type 40) EP/NF); a mixture of hard fat EP/NF/JPE, glyceryle monooleate (type 40) EP/NF (commercially available as OVUCIRE WL 2944 (mixture of hard fat EP/NF/JPE (and) glyceryle monooleate (type 40) EP/NF)); and a mixture of various hard fats (commercially available as WITESPOL (hard fats); Sasol Germany GmbH, Hamburg). In various embodiments, the viscosity of formulations in accordance with various embodiments may comprise from about 50 cps to about 1000 cps at 25° C.

In other embodiments, one or more muco-adherent agents may be used to assist with mucosal absorption of the solubilized estradiol. For example, polycarbophil may be used as an acceptable muco-adherent agent. Other agents include, for example and without limitation, poly (ethylene oxide) polymers having a molecular weight of from about 100,000 to about 900,000, chitosans carbopols including polymers of acrylic acid crosslinked with allyl sucrose or allyl pentaerythritol, polymers of acrylic acid and C10-C30 alkyl acrylate crosslinked with allyl pentaerythritol, carbomer homopolymer or copolymer that contains a block copolymer of polyethylene glycol and a long chain alkyl acid ester and the like. Various hydrophilic polymers and hydrogels may be used. In various embodiments, the hydrophilic polymer will swell in response to contact with vaginal or other bodily secretions, enhancing moisturizing and muco-adherent effects. The selection and amount of hydrophilic polymer may be based on the selection and amount of pharmaceutically acceptable solubilizing agent chosen. The formulation includes a hydrophilic polymer but optionally excludes a gelling agent. In embodiments having a hydrogel, from about 5% to about 10% of the total mass may comprise the hydrophilic polymer. In further embodiments, hydrogels may be employed. A hydrogel may comprise chitosan, which swell in response to contact with water. In various embodiments, a cream formulation may comprise PEG-90M.

In additional embodiments, formulations of the present disclosure may include one or more thermoreversible gels, typically of the hydrophilic nature including for example and without limitation, hydrophilic sucrose and other saccharide-based monomers (U.S. Pat. No. 6,018,033, which is herein incorporated by reference).

In other embodiments, a lubricant may be used. Any suitable lubricant may be used, such as for example lecithin. Lecithin may comprise a mixture of phospholipids.

In additional embodiments, an antioxidant is used. Any suitable anti-oxidant may be used such as, for example and without limitation, butylated hydroxytoluene.

In various embodiments, a pharmaceutical formulation comprises about 20% to about 80% solubilizing agent by weight, about 0.1% to about 5% lubricant by weight, and about 0.01% to about 0.1% antioxidant by weight.

The choice of excipient will, to a large extent, depend on factors such as for example and without limitation, the effect of the excipient on solubility and stability. Additional excipients used in various embodiments may include colorants and preservatives. Colorants, for example, may comprise about 0.1% to about 2% by weight. Preservatives may, for example and without limitation, comprise methyl and propyl paraben, for example, in a ratio of about 10:1, and at a proportion of about 0.005% and 0.05% by weight.

As is with all solubilizing agents, excipients and any other additives used in the formulations described herein, each is to be non-toxic, pharmaceutically acceptable and compatible with all other ingredients used.

Further provided herein are methods for the treatment of VVA and/or estrogen-deficient urinary states comprising administering to a female, typically a human, in need of treatment a non-toxic and pharmaceutically effective dose of a formulation as further provided herein

As referenced above, the formulations of the present disclosure are generally vaginally administered via capsules such as soft capsules, including soft gelatin capsules. It is desirable to prepare these soft capsules such that they disintegrate to the extent that substantially all of the solubilized estradiol is released upon disintegration, providing rapid absorption of the solubilized estradiol and minimal to no capsule residue.

Additional objects of the present disclosure include: providing increased patient ease of use while potentially minimizing certain side effects from inappropriate insertion, minimizing incidence of vulvovaginal mycotic infection compared to incidence of vulvovaginal mycotic infection due to usage of Vagifem and other currently available products and; decreased resultant genital pruritus compared to the genital pruritus and/or back pain that may be generated via the use of Vagifem and other currently available products. In illustrative embodiments of the invention, oils are used as solubilizing agents to solubilize estradiol and include medium chain fatty acid esters, (e.g., esters of glycerol, polyethylene glycol, or propylene glycol) and mixtures thereof. In illustrative embodiments, the medium chain fatty acids are C6 to C14 or C6 to C12 fatty acids. In illustrative embodiments, the medium chain fatty acids are saturated, or predominantly saturated, e.g., greater than about 60% or greater than about 75% saturated. In illustrative embodiments, estradiol is soluble in the oils at room temperature, although it may be desirable to warm certain oils initially during manufacture to improve viscosity. In illustrative embodiments, the oil or oil/thickening agent is liquid at between room temperature and about 50° C., e.g., at or below 50° C., at or below 40° C., or at or below 50° C. In illustrative embodiments, GELUCIRE 44/14 (lauroyl macrogol-32 glycerides EP lauroyl polyoxyl-32 glycerides NF lauroyl polyoxylglycerides (USA FDA IIG)) is heated to about 65° C. and CAPMUL MCM is heated to about 40° C. to facilitate mixing of the oil and non-ionic surfactant, although such heating is not necessary to dissolve the estradiol. In illustrative embodiments, the solubility of estradiol in the oil (or oil/surfactant) is at least about 0.5 wt %, e.g., 0.8 wt % or higher, or 1.0 wt % or higher. Illustrative examples of mono- and diglycerides of medium chain fatty acids include, among others, CAPMUL MCM, CAPMUL MCM C10 (glyceryl monocaprate), CAPMUL MCM C8 (glyceryl monocaprylate), and CAPMUL MCM C8 EP (glyceryl monocaprylate). These oils are C8 and C10 fatty acid mono- and diglycerides. Illustrative examples of oils that are triglycerides of medium chain fatty acids include, among others, MIGLYOL 810 and MIGLYOL 812. Illustrative examples of oils that are medium chain fatty acid esters of propylene glycol include, among others, CAPMUL PG-8, CAPMUL PG-2L EP/NF (propylene glycol dilaurate), CAPMUL PG-8 NF (propylene glycol monocaprylate), CAPMUL PG-12 EP/NF (propylene glycol monolaurate) and CAPRYOL (propylene glycol monocaprylate (type II) NF). Other illustrative examples include MIGLYOL 840 (propylene glycol dicaprylate/dicaprate).

Illustrative examples of oils that are medium chain fatty acid esters of polyethylene glycol include, among others, GELUCIRE 44/14 (PEG-32 glyceryl laurate EP), which is polyethylene glycol glycerides composed of mono-, di- and triglycerides and mono- and diesters of polyethylene glycol.

These illustrative examples comprise predominantly medium chain length, saturated, fatty acids (i.e., greater than 50% of the fatty acids are medium chain saturated fatty acids); specifically predominantly C8 to C12 saturated fatty acids.

It will be understood that commercially available fatty acid esters of glycerol and other glycols are often prepared from natural oils and therefore may comprise components additional to the fatty acid esters that comprise the predominant (by weight) component(s) and that therefore are used to characterize the product. Such other components may be, e.g., other fatty acid triglycerides, mono- and diesters, free glycerol, or free fatty acids. So, for example, when an oil/solubilizing agent is described herein as a saturated C8 fatty acid mono- or diester of glycerol, it will be understood that the predominant component of the oil, i.e., >50 wt % (e.g., >75 wt %, >85 wt % or >90 wt %) are caprylic monoglycerides and caprylic diglycerides. For example, the Technical Data Sheet by ABITEC for CAPMUL MCM C8 describes CAPMUL MCM C8 as being composed of mono and diglycerides of medium chain fatty acids (mainly caprylic) and describes the alkyl content as <=1% C6, >=95% C8, <=5% C10, and <=1.5% C12 and higher

By way of further example, MIGLYOL 812 is generally described as a C8-C10 triglyceride because the fatty acid composition is at least about 80% caprylic (C8) acid and capric (C10) acid. However, it can also comprise small amounts of other fatty acids, e.g., less than about 5% of caproic (C6) acid, lauric (C12) acid, and myristic (C14) acid.

Specifically, a product information sheet for MIGLYOL by SASOL provides the composition of fatty acids as follows:

Tests 810 812 818 829 840 Caproic acid (C6:0) max. 2.0 max. 2.0 max. 2 max. 2 max. 2 Caprylic acid (C8:0) 65.0-80.0 50.0-65.0 45-65 45-55 65-80 Capric acid (C10:0) 20.0-35.0 30.0-45.0 30-45 30-40 20-35 Lauric acid (C12:0) max. 2   max. 2   max. 3 max. 3 max. 2 Myristic acid (C14:0) max. 1.0 max. 1.0 max. 1 max. 1 max. 1 Linoleic acid (C18:2) — — 2-5 — — Succinic acid — — — 15-20 —

So, if an embodiment of this invention is described as comprising (or consisting essentially of) a capsule shell, estradiol solubilized in C8-C10 triglycerides, and a thickening agent, it will be understood that the fatty acid esters component of the formulation may be, e.g., MIGLYOL 812 or a similar product.

By way of further illustration, GELUCIRE 44/14 is generally described as lauroyl polyoxyl-32 glycerides, i.e., polyoxyethylene 32 lauric glycerides (which is a mixture of mono-, di-, and triesters of glycerol and mono- and diesters of PEGs) because the fatty acid composition is 30 to 50% lauric acid and smaller amounts of other fatty acids, e.g., up to 15% caprylic acid, up to 12% capric acid, up to 25% myristic acid, up to 25% palmitic acid, and up to 35% stearic acid. The product may also contain small amounts of non-esterified glycols. So, if an embodiment of this invention is described as comprising (or consisting essentially of) a capsule shell, estradiol solubilized in triglycerides, and a thickening agent that is a non-ionic surfactant comprising C8 to C18 fatty acid esters of glycerol and polyethylene glycol, it will be understood that the thickening agent component of the formulation may be, e.g., GELUCIRE 44/14 or a similar product.

Similarly, if an embodiment of this invention is described as comprising (or consisting essentially of) a capsule shell, estradiol solubilized in triglycerides, and a thickening agent that is a non-ionic surfactant comprising PEG-6 stearate, ethylene glycol palmitostearate, and PEG-32 stearate, it will be understood that the thickening agent component of the formulation may be, e.g., TEFOSE 63 or a similar product.

Mixtures of medium chain fatty acid glycerides, e.g., C6-C12, C8-C12, or C8-C10 fatty acid mono- and diglycerides or mono-, di-, and triglycerides are very well suited for dissolving estradiol; good results have been obtained with an oil that is predominantly a mixture of C8-C10 saturated fatty acid mono- and diglycerides. Longer chain glycerides appear to be not as well suited for dissolution of estradiol.

High solubility of estradiol has been obtained in 2-(2-Ethoxyethoxy)ethanol, e.g., TRANSCUTOL and in Propylene glycol monocaprylate, e.g., Capryol™ 90 (Gattefosse).

In various embodiments, the solubilizing agent is selected from at least one of a solvent or co-solvent. Suitable solvents and co-solvents include any mono-, di- or triglyceride and glycols, and combinations thereof.

In addition, other solubilizers include, for example and without limitation, glyceryl mono- and di-caprylates, propylene glycol and 1,2,3-propanetriol (glycerol, glycerin, glycerine).

Illustrative Drug Product(s)

Through extensive trial-and-error testing of various fatty acid esters of glycerol and other glycols, embodiments of the invention have been invented that have one or more favorable characteristics for development as a human drug product. Such favorable characteristics include, e.g., lack of or reduction of irritation relative to otherwise similar formulations, lack of or reduction in vaginal discharge of drug product relative to otherwise similar formulations, lack of or reduction of drug product residue inside the vagina, etc. Non-irritating formulations are formulations that in most uses in most patients, when used as prescribed, does not cause pain, soreness, swelling or irritation inside the vagina such that most patients do not go off treatment prior to completion of a prescribed course of therapy. Non-irritating formulations are also formulations that are non-irritating, as described in the preceding sentence, relative to competing products such as tablets, creams, or other intravaginal estrogen delivery forms. Such illustrative drug products are also easily self-administered by a patient in any position by inserting the encapsulated formulation digitally approximately 2 inches into her vagina without a need for an applicator and with minimal to no corresponding discharge.

Formulations that do not create a residue are formulations that are absorbed and/or dispersed without resulting in particulates or other unpleasant remains of non-absorbed or non-dispersed drug product. Again, lack of residue can be relative to competing products.

Formulations that do not discharge from the vagina are formulations that do not flow or drip out of the vagina. Again, lack of discharge can be relative to competing products.

Such embodiments include an encapsulated liquid pharmaceutical formulation for intra-vaginal delivery of estradiol, said formulation comprising estradiol that is at least about 90% solubilized in one or more C6 to C14 fatty acid mono-, di-, or triesters of glycerol and a thickening agent.

A more specific such embodiment is such formulation wherein the estradiol is solubilized (e.g., >90% solubilized) in one or more C6 to C12 fatty acid mono-, di-, or triesters of glycerol, e.g., one or more C6 to C14 triglycerides, e.g., one or more C6 to C12 triglycerides, such as one or more C8-C10 triglycerides.

In such general and more specific embodiments, the thickening agent can be a non-ionic surfactant, e.g., a polyethylene glycol saturated or unsaturated fatty acid ester or diester. In certain such embodiments, the non-ionic surfactant comprises a polyethylene glycol long chain (C16-C20) fatty acid ester and further comprises an ethylene glycol long chain fatty acid ester, such as PEG-fatty acid esters or diesters of saturated or unsaturated C16-C18 fatty acids, e.g., oleic, lauric, palmitic, and stearic acids. In certain such embodiments, the non-ionic surfactant comprises a polyethylene glycol long chain saturated fatty acid ester and further comprises an ethylene glycol long chain saturated fatty acid ester, such as PEG- and ethylene glycol-fatty acid esters of saturated C16-C18 fatty acids, e.g., palmitic and stearic acids. Such non-ionic surfactant can comprise PEG-6 stearate, ethylene glycol palmitostearate, and PEG-32 stearate, such as but not limited to TEFOSE 63.

In certain such embodiments, the non-ionic surfactant employed as the thickening agent is not hydrophilic and has good emulsion properties. An illustrative example of such surfactant is TEFOSE 63, which has a HLB value of about 9-10.

As noted above, such formulations are liquid at room temperature, not gels, hard fats, or any other solid form. The thickening agent serves to increase viscosity, e.g., up to 10,000 cP (10,000 mPa-s), typically to no more than 5000 cP, and more typically to between 50 and 1000 cP. In some such embodiments, the non-ionic surfactant, e.g., GELUCIRE or TEFOSE, may be solid at room temperature and require melting to effect mixing with the estradiol solubilized in fatty acid-glycol esters but the resultant formulation is advantageously liquid, not solid.

The formulation of such embodiments is typically encapsulated in a soft gelatin capsule or other soft capsule.

Typically, such formulations do not comprise a bioadhesive (i.e., mucoadhesive) agent, a gelling agent, or a dispersing agent, or, at least, do not comprise one or two of such components.

In more specific such formulations, the capsule shell, the active pharmaceutical ingredient, the fatty acid esters and the thickening agent are the only essential ingredients. Non-essential ingredients, e.g., colorants, antioxidants or other preservatives, etc., may, of course, be included but other ingredients in amounts that would materially change the solubility of the estradiol, the PK of the encapsulated formulation, the irritancy, vaginal discharge, intravaginal residue, etc., e.g., other oils or fatty acid esters, lecithin, muco-adherent agents, gelling agents, dispersing agents, or the like would not be included. Such embodiments of the invention may be described as consisting essentially of the capsule shell, the active pharmaceutical ingredient, the fatty acid esters and the thickening agent, as described in the immediately preceding paragraphs describing illustrative embodiments discovered to have favorable characteristics.

As an example of such embodiments discovered to have such favorable characteristics is mentioned the product identified in Example 3, below, as “Trial 5”.

EXAMPLES

In various embodiments, a vehicle system is created by dissolving an active pharmaceutical ingredient (e.g., estradiol) in one or more pharmaceutically acceptable solubilizing agents. A vehicle system may then be combined with a gel mass to create a final formulation suitable for use in, for example, a vaginal suppository. In that regard, in various embodiments, one or more vehicle systems may be combined with one or more gel masses. Other excipients may also be included in the vehicle system in various embodiments.

Example 1

Formulation: Vehicle System

In various embodiments, estradiol active pharmaceutical ingredient is procured and combined with one or more pharmaceutically acceptable solubilizing agents. Estradiol may be in micronized form or non-micronized form. In various embodiments, the final formulation comprises estradiol in a dosage strength of from about 1 mcg to about 25 mcg.

Estradiol is combined with various pharmaceutically acceptable solubilizing agents in various embodiments. As described above, CAPMUL MCM, MIGLYOL 812, GELUCIRE 39/01, GELUCIRE 43/01, GELUCIRE 50/13, and TEFOSE 63 (\may, alone or in various combinations, be used as a pharmaceutically acceptable solubilizing agent in connection with estradiol.

Solubility of estradiol may affect final formulation stability and uniformity, so care should be taken when selecting an appropriate vehicle system. It is noted that surfactants are typically amphiphilic molecules that contain both hydrophilic and lipophilic groups. A hydrophilic-lipophilic balance (“HLB”) number is used as a measure of the ratio of these groups. It is a value between 0 and 20 which defines the affinity of a surfactant for water or oil. HLB numbers are calculated for nonionic surfactants, and these surfactants have numbers ranging from 0-20. HLB numbers >10 have an affinity for water (hydrophilic) and number <10 have an affinity of oil (lipophilic).

In that regard, GELUCIRE 39/01 and GELUCIRE 43/01 each have an HLB value of 1. GELUCIRE 50/13 has an HLB value of 13. TEFOSE 63 has an HLB value of between 9 and 10.

Various combinations of pharmaceutically acceptable solubilizing agents were combined with estradiol and examined. TABLE 1 contains the results. TABLE 1 contains the following abbreviations: CAPMUL MCM (“MCM”), GELUCIRE 39/01 (“39/01”), GELUCIRE 43/01 (“43/01”), GELUCIRE 50/13 (“50/13”), and TEFOSE (“Tefose 63”).

TABLE 1 Physical Physical Melting Dispersion Vehicle state @ Room state @ 37° C. Viscosity Time @ in water # system Ratio Temperature after ~30 minutes cps 37° C. 37° C. 1 MCM: 39/01 8:2 Solid Clear liquid 50 @ Start: 6 min Small oil 37° C. Finish: 12 min drops on top 2 MCM: 39/01 7:3 Solid Clear liquid Start: 9 min Finish: 19 min 3 MCM: 39/01 6:4 Solid Clear liquid Start: 20 min Finish: 32 min 4 MCM: 43/01 8:2 Solid Liquid with solid particles 5 MCM: 43/01 7:3 Solid Liquid with solid particles 6 MCM: 50/13 9:1 Liquid/ Liquid/ 140@ Clear after Uniformly cloudy cloudy cloudy 25° C. 20 min dispersion 7 MCM: 50/13 8:2 Liquid/ Liquid/ 190@ Uniformly cloudy cloudy cloudy 25° C. dispersion 8 MCM: 50/13 7:3 Semisolid Semisolid 9 MCM: 9:1 Semisolid Liquid/ 150@ Start: 1 min Uniformly cloudy TEFOSE 63 cloudy 25° C. Finish: 5 min dispersion 10 MCM: 8:2 Semisolid Semisolid 240@ Uniformly cloudy TEFOSE 63 25° C. dispersion 11 MCM: 7:3 Semisolid Semisolid 380@ Semisolid Uniformly cloudy TEFOSE 63 25° C. after 30 min dispersion at 37° C., doesn't melt at 41° C. 12 MIGLYOL 812: 9:1 Semisolid Semisolid 140@ 2 phases, 50/13 25° C. oil on top 13 MIGLYOL 812: 9:1 Liquid/ Liquid/ 90@ Start: 1 min 2 phases, TEFOSE 63 cloudy cloudy 25° C. Finish: 5 min oil on top

Vehicle systems in TABLE 1 that were liquid or semisolid at room temperature were tested using a Brookfield viscometer (Brookfield Engineering Laboratories, Middleboro, Mass.) at room temperature. Vehicle systems appearing in TABLE 1 that were solid at ambient temperature were tested using a Brookfield viscometer at 37° C.

Vehicle systems appearing in TABLE 1 that were solid were placed at 37° C. to assess their melting characteristics. The results are in TABLE 1. It is noted that vehicle system 11 in TABLE 1 did not melt at 37° C. or 41° C.

A dispersion assessment of the vehicle systems appearing in TABLE 1 was performed. The dispersion assessment was performed by transferring 300 mg of each vehicle system in 100 ml of 37° C. water, without agitation, and observing for mixing characteristics.

Example 2

Formulation: Gel Mass

In various embodiments, a vehicle system may be combined with a gel mass. A gel mass may comprise, for example, gelatin (e.g., Gelatin, NF (150 Bloom, Type B)), hydrolyzed collagen (e.g., GELITA®, GELITA AG, Eberbach, Germany), glycerin, sorbitol special, and/or other suitable materials in varying proportions. Sorbitol special may be obtained commercially and may tend to act as a plasticizer and humectant.

Gel masses A through F were prepared according to the formulations in TABLE 2. Gel masses A through F differ in the proportion of one or more components, for example.

TABLE 2 Gel A Gel B Gel C Gel D Gel E Gel F Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Gelatin, NF (150 41.0 41.0 41.0 41.0 43.0 43.0 Bloom, Type B) Glycerin 99.7%, 6.0 6.0 6.0 6.0 18.0 18.0 USP Sorbitol 15.0 15.0 15.0 15.0 Special, USP GELITA 3 3.0 (hydrolyzed collagen) Citric acid 0.1 0.5 1 0.1 Purified Water 35.0 37.9 37.5 37.0 36.0 38.9 Total 100.0 100.0 100.0 100.0 100.0 100.0 Dissolution gel 48 min 50 min 75 min 70 min strips, Avg of 3 (42, 45, 58) (50, 51, 50) (76, 75, 74) (70, 71, 70) (500 ml DH2O, 50 rpm @ 37° C.) Dissolution gel 72 min 82 min strips, Avg of 3 70 min 84 min (500 ml pH 4 buffer, 50 rpm @ 37° C.)

Each gel mass A through F was prepared at a temperature range from about 45° C. to about 85° C. Each molten gelatin mass A through F was cast into a film, dried and cut into strips. The strips were cut into uniform pieces weighing about 0.5 g, with about 0.5 mm thickness. Strips were placed into a USP Type 2 dissolution vessel in either water or pH 4 buffer solution and the time for them to completely dissolve was recorded and listed in TABLE 2. It is noted that gel mass A has the fastest dissolution in both water and pH 4 buffer solution.

Example 3

Formulation: Final Formulation and Encapsulation

Various combinations of vehicle systems from TABLE 1 and gel masses from TABLE 2 were prepared. The combinations are shown in TABLE 3.

TABLE 3 Batch Size Trial Vehicle system Ratio g Gel 1 MCM:39/01 8:2 750 A 2 MCM:50/13 8:2 750 A 3 MCM:TEFOSE 63 8:2 750 A 4 MCM:TEFOSE 63 8:2 750 B 5 MIGLYOL 812:TEFOSE 63 9:1 750 A

Estradiol was combined with each vehicle system so that about 10 mcg of estradiol was contained within 300 mg of each vehicle system. Batch size was as listed in TABLE 3. To encapsulate the vehicle system, each 300 mg of vehicle system was combined with about 200 mg of the listed gel mass. Thus, for example, in Trial 1, MCM:39/01 in an 8:2 ratio was combined with gel A and 10 mcg of estradiol. In each final dosage, Trial 1 comprised 300 mg of vehicle system, 200 mg of gel mass and 10 mcg of estradiol. It should be noted, however, that in various embodiments the total mass of vehicle system, gel mass, and estradiol may be from about 100 mg to about 1000 mg.

Each combination of vehicle system, estradiol, and gel mass may be suitable for use in, for example, a vaginal suppository.

Example 4

Estradiol Solubility

In various experiments, suitable solvents were determined for providing sufficient solubility to make 2 mg of estradiol in a 100 mg fill mass, with a desired goal of achieving ˜20 mg/g solubility for estradiol. Initial solubility experiments were done by mixing estradiol with various solvents, saturate the solution with the estradiol, equilibrate for at least 3 days and filter the un-dissolved particles and analyzing the clear supernatant for the amount of estradiol dissolved by HPLC.

Estradiol solubility experiments were performed. From this list at least one item (e.g. propylene glycol) is known to be unsuitable for encapsulation.

TABLE 4 Ingredient Solubility (mg/g) PEG 400 105*  Propylene Glycol 75* Polysorbate 80 36* TRANSCUTOL HP 141  CAPMUL PG8  31.2 *Literature reference—Sable, E.G. (1987) The Physicochemical Properties of Oestradiol, J Pharm and Biomed Analysis, 5, 635-640.

In further solubility studies, estradiol was soluble at at least 6 mg/gm MIGLYOL TRANSCUTOL in ratios of 81:19 to 95:5, in MIGLYOL; ethanol at 91:11, and in MIGLYOL:CAPMUL PG8 at 88:11, but not in MIGLYOL:TRANSCUTOL at 96:4, MIGLYOL:Labrasol at 70:30 to 80:20, or MIGLYOL:CAPMUL PG8 at 86:14.

Example 5

Process

With reference to FIG. 1, a method of making a fill material 100 is shown. Step 102 comprises heating a solubilizing agent to 40° C.±5° C. Heating may be accomplished through any suitable means. The heating may be performed in any suitable vessel, such as a stainless steel vessel. The solubilizing agent may be any such solubilizing agent described herein, for example, CAPMUL MCM.

Step 104 comprises mixing GELUCIRE with the solubilizing agent. As used herein, any form of GELUCIRE may be used in step 104. For example, one or more of GELUCIRE 39/01, GELUCIRE 43/01, GELUCIRE 50/13. may be used in step 104. Mixing may be facilitated by an impeller, agitator, or other suitable means. Step 104 may be performed under an inert or relatively inert gas atmosphere, such as nitrogen gas. Mixing may be performed in any suitable vessel, such as a stainless steel vessel.

Step 106 comprises mixing estradiol into the mixture of the solubilizing agent and GELUCIRE. The estradiol may be mixed in micronized or nonmicronized form. Mixing may occur in a steel tank or other acceptable container. Mixing may be facilitated by an impeller, agitator, or other suitable means. Step 106 may be performed under an inert or relatively inert gas atmosphere, such as nitrogen gas. In various embodiments, however, the addition of estradiol may be performed prior to step 104. In that regard, in various embodiments, step 106 is performed prior to step 104.

Step 110 comprises preparing the gel mass. Any of the gel masses described herein may be used in step 110. In that regard, gelatin (e.g., Gelatin, NF (150 Bloom, Type B)), hydrolyzed collagen, glyercin, and/or other suitable materials may be combined at a temperature range from about 45° C. to about 85° C. and prepared as a film. Mixing may occur in a steel tank or other acceptable container. Mixing may be facilitated by an impellor, agitator, or other suitable means. Step 110 may be performed under an inert or relatively inert gas atmosphere, such as nitrogen gas. Step 112 comprises degasing. The resulting mixture from step 112 may comprise a fill material suitable for production into a softgel capsule.

In step 112, a soft gel capsule is prepared by combining the material obtained in step 106 with the gel mass of step 110. The gel film may be wrapped around the material, partially or fully encapsulating it. The gel film may also be injected or otherwise filled with the material obtained in step 106.

Step 112 may be performed in a suitable die to provide a desired shape. Vaginal soft gel capsules may be prepared in a variety of geometries. For example, vaginal soft gel capsules may be shaped as a tear drop, a cone with frustoconical end, a cylinder, a cylinder with larger “cap” portion, or other shapes suitable for insertion into the vagina. Vaginal soft gel capsules in accordance with various embodiments may or may not be used in connection with an applicator.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the spirit or scope of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.

Likewise, numerous characteristics and advantages have been set forth in the preceding description, including various alternatives together with details of the structure and function of the devices and/or methods. This disclosure is intended as illustrative only and as such is not intended to be exhaustive. It will be evident to those skilled in the art that various modifications may be made, especially in matters of structure, materials, elements, components, shape, size and arrangement of parts including combinations within the principles of the disclosure, to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. To the extent that these various modifications do not depart from the spirit and scope of the appended claims, they are intended to be encompassed therein. 

1. An encapsulated liquid pharmaceutical formulation for intra-vaginal delivery of estradiol, the formulation comprising estradiol that is solubilized in one or more C6 to C14 fatty acid mono-, di-, or triesters of glycerol or one or more other glycols.
 2. The formulation of claim 1, wherein the estradiol is fully solubilized, wherein the formulation further comprises a thickening agent, and wherein the fatty acids comprise predominantly (>50 wt %) one of the following: a) C6 to C12 fatty acids, b) C6 to C10 fatty acids, c) C8 to C 12 fatty acids, or d) C8 to C10 fatty acids.
 3. The formulation of claim 1, wherein the estradiol is solubilized in one of the following: a) one or more C6 to C14 fatty acid mono-, di-, or triesters of glycerol; or b) one or more C6 to C12 fatty acid mono-, di-, or triesters of glycerol; or c) one or more C6 to C14 fatty acid triesters of glycerol; or d) one or more C6 to C12 fatty acid triesters of glycerol; or e) one or more C8 to C10 fatty acid triesters of glycerol.
 4. The formulation of any one of claim 1, 2, or 3 further comprising a thickening agent that is a non-ionic surfactant.
 5. The formulation of claim 4, wherein the non-ionic surfactant comprises a polyethylene glycol fatty acid ester.
 6. The formulation of claim41, wherein the non-ionic surfactant has a HLB value of 9 to
 10. 7. The formulation of claim 5, wherein the non-ionic surfactant comprises a polyethylene glycol long chain fatty acid ester and further comprises an ethylene glycol long chain fatty acid ester.
 8. The formulation of claim 7, wherein the non-ionic surfactant comprises PEG-6 stearate, ethylene glycol palmitostearate, or PEG-32 stearate.
 9. The formulation of claim 5, wherein the non-ionic surfactant comprises C8 to C18 fatty acid esters of glycerol and polyethylene glycol.
 10. The formulation of any one of the preceding claims, wherein the formulation has a viscosity of less than 10,000 cP.
 11. The formulation of claim 9, wherein the formulation has a viscosity of less than 5000 cP.
 12. The formulation of claim 11, wherein the formulation has a viscosity of 50 to 1000 cP.
 13. The formulation of any one of the preceding claims, wherein the non-ionic surfactant comprises a polyethylene glycol fatty acid ester and has a HLB value of 9 to
 10. 14. The formulation of any one of the preceding claims, wherein the formulation is encapsulated in a capsule, and wherein the capsule is a soft gelatin capsule or other soft capsule.
 15. The formulation of any one of the preceding claims, wherein the formulation does not comprise at least one of a bioadhesive agent, a gelling agent, or a dispersing agent.
 16. The formulation of claim 1, providing the formulation does not include a hydrophilic gel-forming bioadhesive agent.
 17. The formulation of claim 16, wherein the formulation does not include at least one of carboxyvinylic acids, hydroxypropylcellulose, carboxymethylcellulose, gelatin, xanthane gum, guar gum, aluminum silicate or mixtures thereof as the hydrophilic gel-forming bioadhesive agent.
 18. The formulation of claim 1, wherein the formulation does not include a gelling agent.
 19. An encapsulated pharmaceutical formulation of claim 18, providing the formulation does not include hydrophobic colloidal silica as the gelling agent.
 20. The formulation of claim 1, providing the formulation does not include a hydrophilic gel-forming bioadhesive agent or a gelling agent.
 21. The formulation of claim 1, wherein a soft capsule is used for the encapsulation.
 22. The formulation of claim 21, wherein the capsule is a soft gelatin capsule.
 23. The formulation of claim 22, wherein the estradiol has a dosage strength from about 1 microgram to about 25 micrograms.
 24. The formulation of claim 23, wherein the estradiol dosage strength is from about 10 micrograms to about 25 micrograms.
 25. The formulation of claim 23, wherein the AUC of circulating blood level concentrations of estradiol following intra-vaginal administration is bioequivalent to the AUC of circulating blood level concentrations following administration of a reference drug. 26.-31. (canceled) 